Best Time to Buy and Sell Stock III

Best Time to Buy and Sell Stock III

Say you have an array for which the ith element is the price of a given stock on day i.

Design an algorithm to find the maximum profit. You may complete at most two transactions.

Note: You may not engage in multiple transactions at the same time (i.e., you must sell the stock before you buy again).

Input: [3,3,5,0,0,3,1,4]
Output: 6

Input: [1,2,3,4,5]
Output: 4

Input: [7,6,4,3,1]
Output: 0

class Solution {

public:

    int maxProfit(vector<int>& prices) 

    {

          int debit_t1 = INT_MIN, credit_t1 = 0;

        int debit_t2 = INT_MIN, credit_t2 = 0;

        for(int i = 0; i < prices.size(); ++i){

            debit_t1 = max(debit_t1, -prices[i]);

            credit_t1 = max(credit_t1, debit_t1 + prices[i]);

            debit_t2 = max(debit_t2, credit_t1 - prices[i]);

            credit_t2 = max(credit_t2, debit_t2 + prices[i]);

        }

        return credit_t2;

    }

};